1. Field of Invention
This invention relates generally to electrostatic display apparatus and particularly to such apparatus in which an electrostatic image passes a magnetic toner, is magnetically toned, and may be inspected at an inspection station; at the option of the operator, the toned electrostatic image is passed to a fusing station to become a permanent image, or withdrawn to the magnetic toning-detoning station, wherein the magnetic toner removes the toner; the blank strip may be reused by being reimaged and retoned.
2. Prior Art
The ordinary electrostatic display apparaus contemplates the production of copies which are permanent. Usually no provision is made for inspection of the copy before it is made permanent (fused) because the person operating the copier knows that he is copying a particular pre-selected display. However, in systems wherein innumerable bits of information are stored and called up for use, when a particular bit of information is retrieved and electrostatically reproduced, it is desirable to inspect the toned but unfused copy to determine whether it is a useful bit of information, before it is made permanent by fusing, for then it might be a useless bit of information. In some systems, there may be a central pool of available stored information that is subject to being recalled and copied at numerous terminals. A display of the stored information on the face of the cathode-ray tube may not be part of the system. The information may be transferred to a strip as a latent electrostatic image, toned, and fused. If the xerographic print is not a useful one, the strip is discarded and this practice may become wasteful and costly. Thus it becomes desirable to preview the unfused image to determine whether it is useful and should be made permanent, or should be discarded. Such an apparatus is shown in U.S. Pat. No. 3,973,846 issued Aug. 10, 1976 to Sullivan et al. where the image is previewed before it is returned past a magnetic toner for being fused.